The present invention relates generally to fluid delivery devices. More particularly, the invention concerns an improved apparatus for delivery of basal and bolus doses of medicinal fluid to a patient that includes internal thermo- and magnetically-responsive energy sources for controllably expelling the fluid from the apparatus.
The oral route is the most frequent route of drug administration. Oral administration is relatively easy for most patients and rarely causes physical discomfort. However, many medicinal agents require a parenteral route of administration thus bypassing the digestive system and precluding degradation by the catalytic enzymes in the digestive tract and the liver. The use of more potent medications at elevated concentrations has also increased the need for accuracy in controlling the delivery of such drugs. The delivery device, while not an active pharmacologic agent, may enhance the activity of the drug by medicating its therapeutic effectiveness. Certain classes of new pharmacologic agents posses a very narrow range of therapeutic effectiveness, for instance, too small a dose results in no effect, which to great a dose results in toxic reaction.
In the past, prolonged infusion of fluids has generally been accomplished using gravity flow means coupled with electronic based controls and typically involve the use of intravenous administration sets and the familiar bottle or solution bag suspended above the patient. Such methods are cumbersome, imprecise and, generally non-ambulatory requiring bed confinement of the patient. Periodic monitoring of the apparatus by the nurse or doctor is required to detect malfunctions of the infusion apparatus.
Devices of the character from which liquid is expelled from a relatively thick-walled bladder by internal stresses within the distended bladder have also been suggested for infusion of medicaments. For example, such bladder, or xe2x80x9cballoonxe2x80x9d type devices, are described in U.S. Pat. No. 3,469,578, issued to Bierman and in U.S. Pat. No. 4,318,400 issued to Perry.
A family of highly unique fluid delivery devices has been developed by the present inventor. These novel devices make use of recently developed elastomeric films, expandable foams and similar materials, which, in cooperation with a base, define a fluid chamber that contains the fluid to be dispensed. The elastomeric film membrane or the expandable member controllably forces fluid within the chamber into outlet fluid flow channels provided in the device. Elastomeric film membrane devices are described in detail in U.S. Pat. No. 5,205,820 issued to the present inventor. U.S. Pat. No. 5,468,226, also issued to the present inventor, describes various types of expandable cellular elastomers and elastomeric foams used as the energy source of the fluid delivery device for expelling fluid from various physical forms of the fluid delivery device. Because of the pertinence of U.S. Pat. Nos. 5,205,820 and 5,468,226, these patents are hereby incorporated herein by reference in their entirety as though fully set forth herein. U.S. Pat. No. 5,961,492 entitled Fluid Delivery Device with Temperature Controlled Energy Source, in which the present inventor is named as a co-inventor is also incorporated by reference as though fully set forth herein. Another patent issued to the present invention, namely U.S. Pat. No. 5,776,103, describes a fluid delivery device with a bolus injection site.
The apparatus of the present invention, comprises a unique, implantable unit that makes use of novel thermo- and electro-stimulated gel materials as energy sources for delivery to the patient of both basal and bolus doses of medicinal fluids. By way of example, the apparatus of the invention can be used for both the continuous basal infusion of a variety of beneficial agents such as heparin, morphine, insulin and like agents as well as for the bolus delivery of such fluids as may be required. With this type of construction, if, for example, the apparatus is being used for basal delivery of insulin over an extended period of time, should a bolus delivery of medication be required to manage an anticipated increase in blood sugar, such a bolus delivery can be quickly and easily accomplished thereby eliminating the need for a direct subdermal injection at an alternate site on the individual""s body. In similar manner, the implantable device of the invention can be used to precisely administer both basal and bolus delivery of a number of types of beneficial agents to the patient.
It is an object of the present invention to provide a technically advanced, fluid delivery apparatus for both basal and bolus infusion of medicinal fluids into a patient. More particularly, it is an object of the invention to provide an apparatus of such a character that is implantable into the patient""s body and includes novel light, thermal, magnetically and electrically stimulated polymer gel materials which uniquely function as internal energy sources for controllably expelling the medicinal fluids from the device.
Another object of the invention is to provide an implantable fluid delivery apparatus that can be used for the precise infusion of various pharmaceutical fluids into the patient at controlled rates over extended periods of time.
Another object of the invention is to provide an apparatus of the aforementioned character that is very small, is of a simple construction and yet is highly reliable in operation.
Another object of the invention is to provide an apparatus that embodies as one of its stored energy sources, a soft, pliable, semi-solid, thermo-responsive mass that is controllably heated by an external stimulus in a manner to controllably expel basal doses of medication to the patient.
Another object of the invention is to provide an apparatus as describe in the preceding paragraph in which the heat expandable mass is specifically tailored to provide precise, predictable protocol delivery of the medicinal agent stored within the reservoir of the device.
Another object of the invention is to provide an apparatus that embodies as the other of its stored energy sources, a magnetically responsive mass, such as a ferrogel which is stimulated in a manner to controllably deliver bolus doses of medication to the patient.
Another further object of the invention is to provide an apparatus of the character described in which the thermo- and magnetically responsive stored energy sources can be constructed from various types of polymeric conformable materials such as phase transition gels.
Another object of the invention is to provide an apparatus that embodies as one of its stored energy sources, a soft, pliable, semi-solid mass that is responsive to light in a manner to controllably expel basal doses of medication to the patient.
Another object of the invention is to provide an apparatus as described in the preceding paragraph in which the light stimulated mass is specifically tailored to provide precise, predictable protocol delivery of the medicinal agent stored within the reservoir of the device.
Another object of the invention is to provide an apparatus of the character described in the preceding two paragraphs that embodies as another energy source, an electrically responsive mass, such as a laminate gel construction which is stimulated in a manner to controllably deliver bolus doses of medication to the patient.
Another object of the invention is to provide stored energy sources of the character described in the preceding paragraphs which comprise blends or laminate constructions of phase transition gels that will enable the achievement of multi-rate delivery protocols.
Another object of the invention is to provide an implantable device of the character described that includes fill means for filing the cooperating reservoirs of the device.
Another object of the invention is to provide an implantable fluid delivery device as described in the preceding paragraphs that includes physiological sensor means for sensing physiological changes in the patient""s body.
Another object of the invention is to provide an apparatus of the character described which, due to its unique construction, can be manufactured inexpensively in large volume by automated machinery.
Another object of the invention is to provide an implantable fluid delivery device that includes a stored energy source comprising an expandable gel that is stimulated by a heating foil disposed proximate the gel.
Another object of the invention is to provide a device as described in the preceding paragraph which also includes a stored energy source that comprises an expandable ferrogel that is magnetically stimulated to controllably deliver bolus doses of medicament from the device.
Another object of the invention is to provide an implantable fluid delivery device that includes a stored energy source comprising an expandable gel that is stimulated by a light source in the form of a light sheet that is disposed proximate the gel.
Another object of the invention is to provide a device as described in the preceding paragraph which also includes a stored energy source that comprises a laminate gel construction that is electrically stimulated so as to flex in a manner to controllably delivery bolus doses of medicament from the device.
Other objects of the invention will become apparent from the discussion, which follows: